Connected: An Internet Encyclopedia
RFC 1155 - 3.2.3. Defined Types

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### 3.2.3. Defined Types

In addition, new application-wide types may be defined, so long as they resolve into an IMPLICITly defined ASN.1 primitive type, list, table, or some other application-wide type. Initially, few application-wide types are defined. Future memos will no doubt define others once a consensus is reached.

#### 3.2.3.1. NetworkAddress

This CHOICE represents an address from one of possibly several protocol families. Currently, only one protocol family, the Internet family, is present in this CHOICE.

#### 3.2.3.2. IpAddress

This application-wide type represents a 32-bit internet address. It is represented as an OCTET STRING of length 4, in network byte-order.

When this ASN.1 type is encoded using the ASN.1 basic encoding rules, only the primitive encoding form shall be used.

#### 3.2.3.3. Counter

This application-wide type represents a non-negative integer which monotonically increases until it reaches a maximum value, when it wraps around and starts increasing again from zero. This memo specifies a maximum value of 2^32-1 (4294967295 decimal) for counters.

#### 3.2.3.4. Gauge

This application-wide type represents a non-negative integer, which may increase or decrease, but which latches at a maximum value. This memo specifies a maximum value of 2^32-1 (4294967295 decimal) for gauges.

#### 3.2.3.5. TimeTicks

This application-wide type represents a non-negative integer which counts the time in hundredths of a second since some epoch. When object types are defined in the MIB which use this ASN.1 type, the description of the object type identifies the reference epoch.

#### 3.2.3.6. Opaque

This application-wide type supports the capability to pass arbitrary ASN.1 syntax. A value is encoded using the ASN.1 basic rules into a string of octets. This, in turn, is encoded as an OCTET STRING, in effect "double-wrapping" the original ASN.1 value.

Note that a conforming implementation need only be able to accept and recognize opaquely-encoded data. It need not be able to unwrap the data and then interpret its contents.

Further note that by use of the ASN.1 EXTERNAL type, encodings other than ASN.1 may be used in opaquely-encoded data.

Next: 3.3. Encodings

Connected: An Internet Encyclopedia
RFC 1155 - 3.2.3. Defined Types